Musnad Ahmad 32:2013

'Abdullah narrated to us, Abu 'Abdullah al-Sulami narrated to us, Abu Dawud narrated to us, from Shu'bah, from Qatadah, from Anas, who said: I prayed behind the Messenger of Allah (peace and blessings of Allah be upon him), and behind Abu Bakr, and 'Umar, and 'Uthman, and they did not begin the recitation with "In the name of Allah, the Entirely Merciful, the Especially Merciful." Shu'bah said: I said to Qatadah, "Did you hear it from Anas?" He said, "Yes, we asked him about it."